Automatically enable "Tile zoom offset" on macOS in HiDPI mode in Java 9+

[Stereo]

What steps will reproduce the problem?

1. Under Imagery preferences / Tab Settings / Tiles zoom offset, set a zoom offset of 1 or 2, as described on https://josm.openstreetmap.de/wiki/Help/HiDPISupport
2. Restart JOSM
3. Create a new layer
4. Add an imagery layer

What is the expected result?

Imagery layer is displayed in high dpi mode

What happens instead?

No visible difference

Please provide any additional information below. Attach a screenshot if possible.

See ticket, difference between the lat/lon (good) and the imagery (bad)

URL:https://josm.openstreetmap.de/svn/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2020-02-01 01:10:57 +0100 (Sat, 01 Feb 2020)
Build-Date:2020-02-01 00:12:46
Revision:15806
Relative:URL: ^/trunk

Identification: JOSM/1.5 (15806 en_GB) Mac OS X 10.15.2
OS Build number: Mac OS X 10.15.2 (19C57)
Memory Usage: 886 MB / 1820 MB (527 MB allocated, but free)
Java version: 1.8.0_241-b07, Oracle Corporation, Java HotSpot(TM) 64-Bit Server VM
Screen: Display 69733632 1680x1050
Maximum Screen Size: 1680x1050
VM arguments: [-Djava.library.path=/Applications/JOSM.app/Contents/MacOS, -DLibraryDirectory=${HOME}/Library, -DDocumentsDirectory=${HOME}/Documents, -DApplicationSupportDirectory=${HOME}/Library/Application Support, -DCachesDirectory=${HOME}/Library/Caches, -DApplicationDirectory=${HOME}/Applications, -DAutosavedInformationDirectory=${HOME}/Library/Autosave Information, -DDesktopDirectory=${HOME}/Desktop, -DDownloadsDirectory=${HOME}/Downloads, -DMoviesDirectory=${HOME}/Movies, -DMusicDirectory=${HOME}/Music, -DPicturesDirectory=${HOME}/Pictures, -DSharedPublicDirectory=${HOME}/Public, -DSystemLibraryDirectory=/Library, -DSystemApplicationSupportDirectory=/Library/Application Support, -DSystemCachesDirectory=/Library/Caches, -DSystemApplicationDirectory=/Applications, -DSystemUserDirectory=/Users, -DUserHome=${HOME}, -DSandboxEnabled=true, -DLaunchModifierFlags=0, -DLaunchModifierFlagCapsLock=false, -DLaunchModifierFlagShift=false, -DLaunchModifierFlagControl=false, -DLaunchModifierFlagOption=false, -DLaunchModifierFlagCommand=false, -DLaunchModifierFlagNumericPad=false, -DLaunchModifierFlagHelp=false, -DLaunchModifierFlagFunction=false, -Dapple.laf.useScreenMenuBar=true, -Dcom.apple.macos.use-file-dialog-packages=true, -Dcom.apple.macos.useScreenMenuBar=true, -Dcom.apple.mrj.application.apple.menu.about.name=JOSM, -Dcom.apple.smallTabs=true]
Dataset consistency test: No problems found

Plugins:
+ AddrInterpolation (35248)
+ CommandLine (35297)
+ ImportImagePlugin (35248)
+ Mapillary (1.5.20)
+ MovementAlert (1511141840)
+ OpeningHoursEditor (35250)
+ PicLayer (35313)
+ ShapeTools (1240)
+ alignways (35248)
+ apache-commons (35092)
+ apache-http (35092)
+ areaselector (359)
+ austriaaddresshelper (57)
+ buildings_tools (35248)
+ changeset-viewer (22)
+ conflation (0.6.4)
+ continuosDownload (91)
+ contourmerge (v0.1.6)
+ ejml (35122)
+ geotools (35169)
+ jaxb (35092)
+ jna (35092)
+ jogl (1.2.3)
+ jts (35122)
+ log4j (35092)
+ opendata (35313)
+ openqa (0.1.9)
+ public_transport (35313)
+ reltoolbox (35313)
+ reverter (35313)
+ rex (53)
+ splinex (35248)
+ terracer (35325)
+ todo (30306)
+ turnrestrictions (35313)
+ undelete (35313)
+ utilsplugin2 (35248)
+ wikipedia (1.1.3)

Tagging presets:
+ https://josm.openstreetmap.de/josmfile?page=Presets/NewTags&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/BicycleJunction&preset&zip=1
+ http://osmtools.de/josm/steps.xml
+ https://josm.openstreetmap.de/josmfile?page=Presets/Historic_Stone&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/LaneAttributes&preset&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Towers&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Golf_Course&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/PublicTransportOneClick&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Bus_lanes&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Heritage&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Historical_Objects&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/public_bookcase&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Stolpersteine&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/BuildingPreset&zip=1
+ https://gitlab.com/k127/josm-presets/raw/master/diplomatic.xml

Map paint styles:
- https://josm.openstreetmap.de/josmfile?page=Styles/Lit&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/ParkingLanes&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Surface&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Maxspeed&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Modified&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/LessObtrusiveNodes&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/AddressValidator&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Noname&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Power&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Surface-DataEntry&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/PowerMapping&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Lane_and_Road_Attributes&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/BesideTheRoad_Speed&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/TreeCrownDiameter&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/SlovakiaBicycleRoutes&style&zip=1
- https://github.com/simon04/coloured-addresses.mapcss/raw/master/dist/coloured-addresses.mapcss
- https://josm.openstreetmap.de/josmfile?page=Styles/Coloured_Streets&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Coloured_Suburb&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Cycleways&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/SlovakiaBicycleRoutes&style&zip=1
- https://github.com/GlassOceanos/indoor-JOSM-style/archive/master.zip
- https://josm.openstreetmap.de/josmfile?page=Styles/PublicTransport&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/PTStops&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/SlovakiaBicycleRoutes&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/SimpleRoofTags&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/SimpleBuildingTags&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/HiDPISupport&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/NumberedCycleNodeNetworks&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/NumberedWalkingNodeNetworks&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/AddressValidator&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/NewHighwayColors&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Noname&zip=1

Validator rules:
+ http://www.openrailwaymap.org/validator/openrailwaymap.validator.mapcss
+ https://josm.openstreetmap.de/josmfile?page=Rules/GermanySpecific&zip=1
+ http://www.openrailwaymap.org/validator/de-openrailwaymap.validator.mapcss
+ https://josm.openstreetmap.de/josmfile?page=Rules/MissingWeekdays&zip=1
+ https://raw.githubusercontent.com/nlehuby/transport_mapcss/master/transport.validator.mapcss

Last errors/warnings:
- W: Not a single layer for the name 'Bing Sat': []
- W: No configuration settings found.  Using hardcoded default values for all pools.
- W: Warning: Failed to scan file 'fr.datagouvfr.jar' for module information. Skipping.

[Stereo]

Screenshot showing lat/lon text (good) and imagery (big pixels)

[Don-vip]

Do you get the same behaviour with Java 13? ​https://adoptopenjdk.net/?variant=openjdk13&jvmVariant=hotspot

[Stereo]

Thanks, after installing adoptopenjdk from homebrew it looks a lot better!

[Stereo]

In fact, it looks so good that I think JOSM should warn macOS users if they're still using Java 8, and zoom offset should be set automatically using the method described in ​https://stackoverflow.com/questions/20767708/how-do-you-detect-a-retina-display-in-java

[Don-vip]

Can you please share a screenshot with OpenJDK13, with and without the parameter enabled?

[Stereo]

Java 13 with overzoom

[Stereo]

Java 13 with normal zoom

[Stereo]

Java 13 great text and way rendering

[Stereo]

Text/line rendering on Java 13

[Stereo]

Here's Java 8.

Here's java 13 no overzoom, at roughly the same position. Imagery quality is the same. The overall rendering is already a lot better - compare the changeset button in the left toolbar in java 8 and 13, or the attribution text, for example.

This is Java 13 with overzoom set to 2 (I have no idea what the 'right' scale factor is for my display and resolution):

Text and line drawing looks a lot better on Java 13. I don't have a Java 8 screenshot and never want to reinstall it, so you'll just have to take my word for it :). This is the Potlatch style, which really shows off the quality of the text rendering. In Java 8, everything looked like that power tower icon.

I really, really, really like it.

[Don-vip]

In 15918/josm:

fix #18720 - see #11856 - Automatically enable "Tile zoom offset" in HIDPI mode

[Don-vip]

In 15922/josm:

see #18720 - Headless mode is obviously not an HIDPI screen, as Jenkins wisely reminds us

[skyper]

Milestone 20.2 ?

Sorry, cannot set a milestone from the past

[johsin18]

Patch for setting the default zoom offset based on HiDPISupport class.

[johsin18]

May I suggest to use the existing HiDPI infrastructure in the code, instead of adding PlatformHook.isHighDpiDisplay()?
In addition, always setting a zoom offset of 2 whenever the scaling is not exactly identity, falls short in many cases. See the attached patch for my suggested solution.

[simon04]

@johsin18, since ticket is assigned to the already finished milestone 20.02, please open a separate ticket. This allows to correctly assign improvements to the associated releases. Thanks!

[johsin18]

@simon04 Ok, I have created #19360.